Biological deposits generally refer to deposits of material of biological origin, such as plaque, bacteria, tartar, and calculus that are generally regarded as undesirable for dental hygiene. Dental plaque is a complex organic deposit generated in part by the activity of bacteria upon surfaces of the oral cavity, such as on the teeth, or upon contamination from, for example, food deposits on the teeth, gums, tongue, or cheek. Plaque is an undesirable precursor to tooth decay, periodontal disease and the development of dental caries.
It is desirable to detect plaque deposits in the oral cavity before removing them, for example by using toothbrushes (manual or power), tooth floss, tooth picks, or oral irrigators, as detection indicates the areas at which dental cleaning effort should be focused. Such deposits may be difficult to detect in situ/in vivo on the teeth, gums, tongue, or cheek. It is especially important to detect dental plaque. For detection of plaque it is known to use fluorescence measurement, in which incident radiation is directed at the surfaces of the oral cavity, and fluorescence radiation having characteristics associated with the presence of biological deposits is emitted from the surfaces and is detected.
In the state of the art there are two general methods for detecting dental plaque, using respectively primary fluorescence in which the fluorescence of dental plaque or other dental material itself is monitored, and secondary fluorescence in which surfaces in the oral cavity suspected of bearing plaque are treated with a fluorescent label material which preferentially binds to dental plaque, and the fluorescence emission of the label material on the oral cavity surfaces at which it has bound is detected to indicate the presence of dental plaque. Also know are toothbrush heads having a bundle of optical fibers extending through it to direct incident radiation at a test tooth surface, and to collect emitted radiation from the test tooth surface.
A requirement of such methods is that incident radiation is directed at the surfaces of the oral cavity under examination and that consequent fluorescence emission radiation from those surfaces is collected. The amplitude of that radiation is a function of the amount of biological deposit located on the surface, as well as the distance the light source and detectors are from the surface. Consequently, the actual plaque value detected will fluctuate depending upon such factors, thereby resulting in a plaque value which may not truly depict the condition of plaque on the surface of the oral cavity. Known devices are not known to compensate for distances between the source of radiation and/or sensors and the surface of the oral cavity when determining the amount of biological deposit on the oral cavity surfaces.
Devices and methods for detecting plaque in the oral cavity according to the invention described and claimed herein compensate for the distance between the source and/or optical sensors of the incident radiation and on the oral cavity surface being examined, thus providing a compensated plaque value.